Title:Exploiting the synergy between ALMA and VLT/AO-IFU Abstract: For several years it has been a challenge to study high-z star-forming galaxies using both optical and sub-millimetre spectroscopy. I have proposed an extra- galactic experiment to forge a synergy between the ALMA and VLT telescopes. I use a uniquely suited star-forming galaxy sample selected from the HiZELS coverage in the UDS, COSMOS and SA22 fields. The sample is located near bright stars that aid AO-assisted IFU H-alpha imaging with SINFONI at 0.15'''' resolution. These IFU observations have shown that these galaxies present large ionised gas complexes in rotating disks (approximately 50% of the light is in the form of clumps), allowing an estimate of inclination, asymptotic rotation speed and dynamical mass. I lead a SINFONI-ALMA campaign to follow-up these observations and measure the available reservoir of molecular gas mass via the CO(2--1) emission and the spatial distribution of the cold dust at matched resolution. These observations will provide key insights into the drivers of the star-formation (and its efficiency) at z=0.84, 1.47 and 2.23, near the peak of the cosmic star-formation activity, where galaxies were assembling most of their stellar mass.